Search results for "Interaction"

A Non-Local Two Dimensional Foundation Model

2012

Classical foundation models such as the Pasternak and the Reissner models have been recently reformulated within the framework of non-local mechanics, by using the gradient theory of elasticity. To contribute to the research effort in this field, this paper presents a two-dimensional foundation model built by using a mechanically based non-local elasticity theory, recently proposed by the authors. The foundation is thought of as an ensemble of soil column elements resting on an elastic base. It is assumed that each column element is acted upon by a local Winkler-like reaction force exerted by the elastic base, by contact shear forces and volume forces due, respectively, to adjacent and non-…

Lagrangian finite element modelling of dam–fluid interaction: Accurate absorbing boundary conditions

2007

The dynamic dam-fluid interaction is considered via a Lagrangian approach, based on a fluid finite element (FE) model under the assumption of small displacement and inviscid fluid. The fluid domain is discretized by enhanced displacement-based finite elements, which can be considered an evolution of those derived from the pioneering works of Bathe and Hahn [Bathe KJ, Hahn WF. On transient analysis of fluid-structure system. Comp Struct 1979;10:383-93] and of Wilson and Khalvati [Wilson EL, Khalvati M. Finite element for the dynamic analysis of fluid-solid system. Int J Numer Methods Eng 1983;19:1657-68]. The irrotational condition for inviscid fluids is imposed by the penalty method and con…

Dynamic response of beams excited by moving oscillators: Approximate analytical solutions for general boundary conditions

2023

In this paper, the dynamic response of an Euler-Bernoulli beam with general boundary conditions (BCs) and subject to a moving oscillator is examined. Notably, novel approximate closed-form expressions are determined for the vertical responses of both the beam and the moving oscillator, specifically considering the effect of damping in these systems, commonly omitted in standard approaches in the literature. In this regard, a modal superposition procedure is adopted and combined with an appropriate expansion-based approach of the dynamic response of the system, which naturally arises considering the oscillator-beam mass ratio to be reasonably small. Further, general boundary conditions are t…

Interaction Diagram of a Circular Bar in Torsion and Extension

1995

For a circular bar of perfectly plastic material and subjected to a cyclically variable torque and a constant axial force, the interaction (or generalized Bree) diagram is derived by a direct method in which Melan’s theorem is used to locate the nonratchetting load boundary.

Fluid-structure interaction approach with smoothed particle hydrodynamics and particle-spring systems

2022

This paper presents a novel three-dimensional fluid-structure interaction (FSI) approach, where the meshless smoothed particle hydrodynamics (SPH) method is used to simulate the motion of incompressible fluid flows, whilst structures are represented by a simplified approach based on particle-spring systems. The proposed FSI technique allows to use independent spatial-temporal resolutions for the fluid and structural computational domains. The particle-spring elastic constants are calibrated and relationships with the mechanical material properties, Young's modulus and Poisson's ratio, are determined. Fluid and structure computational domains are separated by interfaces made of triangular el…

Internalizing problems as a mediator in the relationship between low effortful control and internet abuse in adolescence: A three-wave longitudinal s…

2019

Abstract The aim of the study is to examine the relationships between early adolescents' low effortful control, middle adolescents' internalizing problems and late adolescents' Internet abuse, focusing on the mediating role that middle adolescents' internalizing problems may play in the relationship between early adolescents' low effortful control and late adolescents' Internet abuse. The study followed a sample of 482 adolescents (245 boys and 237 girls) from early adolescence (wave 1; mean age = 14.76, SD = 0.63), through middle adolescence (wave 2; mean age = 15.77, SD = 0.61), to late adolescence (wave 3; mean age = 17.88, SD = 0.57). The participants completed self-report questionnaire…

2021

Abstract In an ever-evolving technological landscape that challenges teaching professionals' digital competence, this study complements previous studies by providing an overall picture of teaching professionals' digital competence. We employed regression models on two large-scale assessment data sets on teachers from 11 countries—namely, the Teaching and Learning International Survey (TALIS; n = 50,800) and the Programme for the International Assessment of Adult Competencies (PIAAC; n = 2590)—to investigate through the theoretical lens of digital competence how teaching professionals' skills, attitudes and knowledge distribute and relate, and how they are associated with personal and contex…

Hi, Can I Help? Exploring How to Design a Mental Health Chatbot for Youths

2020

Chatbots represent new opportunities for low-threshold preventive mental health support to youths. To provide needed knowledge regarding how to design chatbots for this purpose, we present an exploratory design study where we designed and evaluated a prototype chatbot to complement the work of school nurses in the school health service. The prototype was designed with particular regard for preventive mental health support. The design process involved school nurses, digital health workers, and youths. Through user insight activities, we identified four types of support to be provided through the chatbot: informational, relational, processual, and referral. We explored these four types of sup…

Female sex workers' use of mobile phones in India: Lessons in effective engagement

2019

Despite the widespread impact of mobile phone technology, research on female sex workers’ (FSWs) access and use of this technology is sparse. This study aimed to document FSWs’ subjective perceptions of the benefits of mobile phone technology as well as examine the potential for its use by nongovernmental organizations (NGOs). Employing a phenomenological study built on in-depth qualitative interviews and focus group discussions with 67 FSWs and 18 staff and leaders from local NGOs in Mumbai and various locations of the Karnataka State in India between January and May 2015. Findings revealed complex trajectories for FSWs regarding accessing, learning about, and using mobile phone technology…

Teacher trainees' experiences of the components of ICT competencies and key factors in ICT competence development in work-based vocational teacher tr…

2022

International journal for research in vocational education and training 9 (2022) 2, S. 146-166